4 The Philippine Journal of Science 1928 



Ceylon ; furthermore, the genus Valeria presents but three spe- 

 cies, one occurring in Ceylon, one in India, and one in the 

 Seychelles. 



Perhaps the most striking feature in the distribution of the 

 dipterocarps is their paucity in eastern Malaysia; that is, in the 

 entire region extending from Celebes southward to Lombok, 

 and eastward through the Moluccas to New Guinea, where only 

 fourteen species in four genera are known. Four of these be- 

 long in the genus Anisoptera, three in the genus Hopea, three 

 in the genus Shorea, and four in the genus Vatica. All of these 

 genera are of wide geographic distribution, represented in most 

 of the regions in which the family occurs. The genera Hopea, 

 Shorea, and Vatica are three of the four large genera in the 

 family. It seems probable, however, that the number of species 

 generally recognized as occurring in eastern Malaysia is too 

 high. Dr. D. F. van Slooten, who is now engaged in a general 

 study of the Dipterocarpaceae of Malaysia, informs me under 

 date of February 4 that, so far as his studies have been com- 

 pleted, he is of the opinion that the two species of Anisoptera 

 described from New Guinea, and perhaps the undescribed one 

 mentioned by Dyer, must be reduced to A. polyandra Blume. He 

 is further of the opinion that the three species of Vatica recorded 

 from the Moluccas should be reduced to a single one, V. papuana 

 Dyer. The reduction in the number of species of Vatica is, 

 however, counterbalanced by two apparently undescribed forms 

 represented in the Buitenzorg Herbarium by imperfect material 

 from Celebes. 



It is perfectly evident that the Eastern Peninsula and the 

 bunda Islands are essentially the regions in which the family 

 has reached its maximum development in genera and in species. 

 India may possibly have supported a much richer dipterocarp 

 fftw f Tfi han t0_day; thiS is es P eci *% P^bable in view 

 of the fact that the comparatively small island of Ceylon, off the 

 southern end of the Indian Peninsula, presents so many more 

 genera and species than does the entire Western Peninsula, 

 id r C Ti. J; , largG devel °P men t of this family in the Sunda 

 Islands, the Eastern Peninsula, and the Philippine* its slight 

 ctraTt ment f ^ eaStern Mala ^ and the peculiar biological 

 SS n of the gr oup (see p. 6), a study of the geographic 

 tt^Tf e D f erocar P ac eae in the entire Malaysian 



region is of very special interest. This interest lies in a logical 



